Gravitomagnetism and Gravitational Waves

The general theory of relativity predicts new phenomena of gravity analogous to those of electromagnetism. Discover how ultra-sensitive experiments have detected the gravitomagnetism of the Earth, and follow the search for elusive gravitational waves that travel through space.

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One of the consequences of Einstein's general theory of relativity is evident in Hubble's picture of the galaxy cluster Abell 2218. Investigate the physics of this phenomenon, called gravitational lensing, and discover how Hubble has used it to study extremely distant galaxies as well as dark matter.

Get a lesson in Einstein's general theory of relativity to understand an effect called gravitational microlensing, which allows astronomers to deduce a planet's existence without recording any light from the planet or its host star. This technique reveals exoplanets that would otherwise go undetected.

Taught by Professor Bradley Schaefer of Louisiana State University, this course shows how ancient Egyptians, Greeks, Indians, Chinese, and other cultures saw the sky. You learn how the Sun, Moon, and stars were their clock, calendar, and compass; constellations encoded their mythologies; and the heavens inspired religious and philosophical ideas,…

Why were the motions of the Sun, Moon, and stars so important to ancient people? Investigate key astronomical directions noticed by all cultures. Then embark on your study of Stonehenge, seeing how it gave birth to the field of archaeoastronomy and to some very curious modern theories.

In the popular mind, Stonehenge was built as a sophisticated astronomical calculator presided over by priestly astronomers called Druids. But is this view dating from the mid-1960s correct? Address the evidence, and survey the archaeological record to discover the most probable function of Stonehenge.

Explore Neolithic tombs and monuments across Europe, discovering an array of alignments toward astronomical events. Start with two sites that are similar to Stonehenge in their clear orientation to the winter solstice: Maes Howe in the Orkney Islands, and Newgrange in Ireland.

Study the astronomical significance of Egypt's Great Pyramid. How did its builders achieve such phenomenal accuracy in the pyramid's alignment to the cardinal directions? Were its air shafts intended to point at stars of special importance? Also evaluate modern claims for the mystical power of pyramids.

Travel to Chaco Canyon, New Mexico, where the Anasazi culture practiced sky-centered rituals a thousand years ago. Look for evidence of their astronomical knowledge, examine their many "sun daggers," and probe the controversial pictograph thought to depict the Crab Nebula supernova explosion in 1054 AD.

Consider the astronomy-based world views of different ancient cultures and how they answered the three big questions: Where did the world come from? What is the nature of the universe? What is its fate? Survey the beliefs of the Greeks, Chinese, Australian aborigines, and other groups, seeking common elements.

Witnessing a meteor fall must have been a strange and awe-inspiring experience for people long ago. Travel around the world to places where meteorites were worshiped and also used as a source of iron, which was rarer than gold before the smelting technology of the Iron Age.

Since no human can touch the sky, any unexpected celestial event must be a divine omen. Reenter this primordial state of mind, seeing eclipses and comets the way they were perceived before the advent of modern science. In the course of this investigation, discover why comets became more feared than…

For centuries, astronomers have struggled to find an explanation for the Star of Bethlehem, recounted in the Gospel of Matthew. Professor Schaefer focuses on a recent theory that has taken scientists and biblical scholars by surprise, due to its success at solving problems that plagued all previous proposals.